1. Field
The present disclosure relates to a fusion protein that includes a polypeptide binding specifically to a constant region of an antibody and a stabilization protein linked to a terminal of the polypeptide, a polynucleotide encoding the fusion protein, a cell including the polynucleotide, a method of preparing the fusion protein, and a method of isolating an antibody by using the fusion protein.
2. Description of the Related Art
Affinity chromatography is a method of isolating a target material by specific binding characteristics with respect to the target material. Examples of the affinity chromatography include protein A affinity chromatography using a protein A having affinity with an immunoglobulin G. The protein A affinity chromatography is wildly used to mass-produce antibodies because 95% or more of high isolation purity can be achieved using a single process only. The protein A affinity chromatography uses selective affinity between a protein A, which is a cell surface protein found in Staphylococcus aureus, and a constant region of immunoglobulin, and is generally used to isolate antibodies.
When conventional protein A affinity chromatography columns are repeatedly used, ligands are likely to leak out, and contaminants generated when the protein A is formed retain an affinity with IgG and continue to form a complex. Thus, it may not be easy to remove the contaminants from an isolated antibody. In addition, the protein A, which is a bacteria protein, needs to be removed because it may cause undesired immune reactions. When antibodies are industrially produced, the manufacturing costs are greatly dependent on the costs for antibody isolation and purification. Since the protein A affinity chromatography is very expensive, despite excellent isolation efficiency of the protein A affinity chromatography, demands for developing alternative methods to the protein A affinity chromatography have increased.
Small polypeptide fragments that are specific to a constant region of an antibody have been introduced as an alternative to the protein A used in the conventional affinity chromatography. However, these polypeptide fragments contain six amino acids and are instable under a strong acid or base environment or at high temperature, and thus are not suitable for isolating high-concentration antibodies.
Thus, there is still a need to develop to methods of isolating an antibody and stable polypeptides that bind specifically to a constant region of an antibody when performing the isolation methods.